Acute kidney injury (AKI) is a common event, especially among individuals undergoing surgery. Short-term complications of AKI are well defined and included, an increased hospital length of stay, an increased cost of hospitalization, and increased risk of short- term mortality. There exists a gap in knowledge regarding the long-term consequences of AKI. Specifically, it remains unknown if AKI episodes contribute to the burden of chronic kidney disease or long-term mortality. As an outcome of the proposed project we aim to determine whether postoperative AKI is a modifiable risk factor for the development or progression of chronic kidney disease or long-term mortality. This application outlines the use of several nation-wide datasets to efficiently determine the impact of varying levels of postoperative AKI on long-term complications. Available data include prospective peri-operative data, longitudinal laboratory, pharmacy and administrative data. Our specific aims are as follows: To determine if postoperative acute kidney injury is subsequently associated with a) loss of kidney function 90 days after surgery and b) an increased rate of decline of long-term renal function; to determine whether severity of postoperative acute kidney injury is associated with end stage kidney disease (ESKD) and/or long-term mortality; and to determine if the rate of decline of kidney function or risk of ESKD and/or long-term mortality associated with postoperative acute kidney injury is consistent across risk subgroups defined by select patient characteristics. Sample size estimates reveal adequate power for each of the aims. We hypothesize that a greater severity of postoperative AKI will be associated with a lower GFR 90 days postoperatively, a greater slope of GFR loss longitudinally and an increased risk of both ESKD and long-term mortality. We are uniquely suited to this application, as we have access to national surgical, lab and administrative data and our group includes a number of individuals with extensive experience in merging and analyzing large complex datasets for identifying novel determinants of chronic kidney disease and mortality. The objective of this application is to determine the impact of postoperative acute kidney injury on chronic kidney disease and survival. Ultimately, if AKI episodes contribute to long-term renal outcomes and/or survival, therapies maybe developed to enhance recovery of AKI, potentially decreasing the burden of chronic kidney disease or improving long-term survival. The proposed cohort will be the largest assembled to determine the long-term consequences of postoperative AKI. Utilizing the methodology proposed, we will be able to determine in an efficient, cost-effective manner if postoperative AKI and its severity is independently associated in a graded manner with a reduction of kidney function 90 days after surgery, with an increased rate of decline of kidney function over 3 years of follow-up, an increased incidence of ESKD and/or an increased risk of long-term mortality. The research proposed is meaningful because demonstrating that episodes of AKI are associated with long-term outcomes has the potential to identify novel interventions to reduce the burden of CKD in the community. Once the AKI- associated burden of CKD has been precisely estimated and modifiable factors have been identified, clinical trials can be performed that may reduce this disease burden. [unreadable] [unreadable] [unreadable]